1. Field of the Invention
The present invention relates to a movable contact used for a sheet having a movable contact for example used for an operation section of an electronic device such as a mobile phone, a sheet having the movable contact, and a switch apparatus using the movable contact and the sheet.
2. Background Art
In recent years, electronic devices such as mobile communication devices such as mobile phones have been developed to have a remarkably small size. Thus, a sheet having a movable contact, which is used to constitute a switch apparatus in an operation section in such an electronic device, also has been required to have a smaller size while maintaining a superior touch, and a long life.
With regards to a movable contact used for the conventional sheet having a movable contact as described above, those shown in FIG. 11 to FIG. 12 have been suggested. The movable contact will be described with reference to the drawings.
FIG. 11 is a cross-sectional view of a conventional movable contact. FIG. 12 is a plan view thereof.
As shown in FIG. 11 and FIG. 12, movable contact 1 has a substantially arch-like shape when viewed from the side in which the center protrudes upwardly and in which a long shape is obtained, when viewed from the top, by cutting upper and lower ends of an outer circular shape so that, the upper and lower ends are parallel to each other.
Movable contact 1 is prepared to have the above shape by sequentially subjecting an elastic thin metal plate to a punching machining by a press metal die and a bending machining.
When movable contact 1 is used, the center part is applied with a depression force and, when a predetermined depression force (also may be called as “pressing force”) is exceeded, the center part elastically inverts to have a shape swelling to the lower side while causing a stepwise touch response (also may be called as “click, touch response”). When the depression force is reduced and is smaller than a predetermined depression force (recovery force), movable contact 1 uses the elastic restoring force to have an original shape while causing a click touch response.
In movable contact 1 having the above shape, upper and lower ends are cut from the outer circular shape so that the upper and lower ends are parallel to each other. Thus, movable contact 1 can be arranged with a higher arrangement efficiency.
With regards to information for a publication of related art for the invention of this application, Japanese Patent Unexamined Publication No. 2005-71783 is known for example.
However, although movable contact 1 of the conventional design has a high arrangement efficiency by the long shape as described above, movable contact 1 conventional design also has a disadvantage in that, when movable contact 1 itself is required to have an outer shape to satisfy requirements by smaller devices in recent, years and is set to have an excessively narrow width, a pressing force may be reduced to cause a weak click touch response, thus preventing movable contact 1 from being practically used.